In wavelength division multiplexing (WDM) systems, arrayed waveguide grating (AWG) multiplexer is a key component. Polymeric AWG multiplexer has recently attracted much attention due to its low cost processing and a p...In wavelength division multiplexing (WDM) systems, arrayed waveguide grating (AWG) multiplexer is a key component. Polymeric AWG multiplexer has recently attracted much attention due to its low cost processing and a potential of integration with other devices. Fluorinated polyether ether ketone (FPEEK) is excellent material for fabrication of optical waveguides due to its low absorption loss at 1.55-μm wavelength and high thermal stability. A 32-channel AWG multiplexer has been designed based on the grating diffraction theory and fabricated using newly synthesized FPEEK. During the fabrication process of the polymer/Si AWG device, spin coating, vaporizing, photolithographic patterning and reactive ion etching (RIE) are used. The AWG multiplexer measurement system is based on a tunable semiconductor laser, an infrared camera and a Peltier-type heater. The device exhibits a wavelength channel spacing of 0.8 nm and a center wavelength of 1548 nm at room temperature.展开更多
Using LiF and YF3 as starting materials,we prepare feed material from fluorides according to the molar ratio of LiF：YF3=51.5：48.5.The anhydrous LiYF4 polycrystalline material is synthesized via the fluoridation proc...Using LiF and YF3 as starting materials,we prepare feed material from fluorides according to the molar ratio of LiF：YF3=51.5：48.5.The anhydrous LiYF4 polycrystalline material is synthesized via the fluoridation process with a dried HF flow at elevated temperature.By charging the feed material and adding a small amount of active carbon powder in a sealed platinum crucible,the crystal can be grown via the vertical Bridgman method in a nonvacuum atmosphere.This is possible because the oxidization and volatilization of the melt is avoided.Using optimum conditions,that is,a growth rate of 0.5-0.6 mm/h and a temperature gradient of 25-30℃/cm across the solid-liquid interface under a furnace temperature of 920-930℃,the colorless crystal LiYF 4 with the size of φ25 × 50 （mm） is successfully grown.The optical transmittance of the crystal is as high as 85% above the absorption edge at 190 nm.The induced absorption bands are observed below 700 nm in the transmission spectrum after the crystal is subjected to a high dose of γ-ray irradiation.展开更多
Raman scattering experiments for nominally pure and uranium doped CaF2 single crystals were presented. In all crystals, the Raman active T2g vibration mode of CaF2 was observed, whose frequency shift and full-width at...Raman scattering experiments for nominally pure and uranium doped CaF2 single crystals were presented. In all crystals, the Raman active T2g vibration mode of CaF2 was observed, whose frequency shift and full-width at half-maximum (FWHM) broadening correspond well with defects and impurities in CaF2 lattice. Additional Raman peaks develop in nominally pure CaF2 with high etch pits density and U6+:CaF2 crystals. Part of additional Raman peaks in the experimental results, which are assumed due to vibration modes from F- interstitials and vacancies, are in well agreement with the theoretical predications by employing the Green-function formulation.展开更多
Recently, ArF iininersion lithography has been considered as a promising method after ArF dry lithography by a factor of refractive index n of the liquid filled into the space between the bottom lens and wafer, in th...Recently, ArF iininersion lithography has been considered as a promising method after ArF dry lithography by a factor of refractive index n of the liquid filled into the space between the bottom lens and wafer, in the case of 193-nm exposure tools, water （n - 1.44） has been found as the best liquid, We explore the NA/σ＇s dependence of depth of focus （DOF） under 3/4 annular and 3/4 quasar illumination by resist imaging simulation, Line/space pairs of line-to-space ratios 1：1, 1：2, 1：4 on binary mask are considered. Finally, we explored the high NA＇s dependency of DOF and gaw~ the explanation for the peak value of DOF through three-beam imaging process, MicroCruiser 2.0, Prolith version 8,0,2 and k2 factor based on the Rayleigh equation.展开更多
基金This work was financially supported by the Science & Technology Council of China (No. TG2000036602 and 2001AA312160)
文摘In wavelength division multiplexing (WDM) systems, arrayed waveguide grating (AWG) multiplexer is a key component. Polymeric AWG multiplexer has recently attracted much attention due to its low cost processing and a potential of integration with other devices. Fluorinated polyether ether ketone (FPEEK) is excellent material for fabrication of optical waveguides due to its low absorption loss at 1.55-μm wavelength and high thermal stability. A 32-channel AWG multiplexer has been designed based on the grating diffraction theory and fabricated using newly synthesized FPEEK. During the fabrication process of the polymer/Si AWG device, spin coating, vaporizing, photolithographic patterning and reactive ion etching (RIE) are used. The AWG multiplexer measurement system is based on a tunable semiconductor laser, an infrared camera and a Peltier-type heater. The device exhibits a wavelength channel spacing of 0.8 nm and a center wavelength of 1548 nm at room temperature.
基金supported by the Natural Science Foundation of Zhejiang Province(No. Y4090057)the Natural Science Foundation of Ningbo City(No.2009610016)+1 种基金the support extended by the Personnel Training Project of the Zhejiang Education Departmentsponsored by the K. C. Wong Magna Fund of Ningbo University
文摘Using LiF and YF3 as starting materials,we prepare feed material from fluorides according to the molar ratio of LiF：YF3=51.5：48.5.The anhydrous LiYF4 polycrystalline material is synthesized via the fluoridation process with a dried HF flow at elevated temperature.By charging the feed material and adding a small amount of active carbon powder in a sealed platinum crucible,the crystal can be grown via the vertical Bridgman method in a nonvacuum atmosphere.This is possible because the oxidization and volatilization of the melt is avoided.Using optimum conditions,that is,a growth rate of 0.5-0.6 mm/h and a temperature gradient of 25-30℃/cm across the solid-liquid interface under a furnace temperature of 920-930℃,the colorless crystal LiYF 4 with the size of φ25 × 50 （mm） is successfully grown.The optical transmittance of the crystal is as high as 85% above the absorption edge at 190 nm.The induced absorption bands are observed below 700 nm in the transmission spectrum after the crystal is subjected to a high dose of γ-ray irradiation.
基金This work was partially supported by the Optics Science and Technology Foundation of Shanghai City under Grant No. 022261053.
文摘Raman scattering experiments for nominally pure and uranium doped CaF2 single crystals were presented. In all crystals, the Raman active T2g vibration mode of CaF2 was observed, whose frequency shift and full-width at half-maximum (FWHM) broadening correspond well with defects and impurities in CaF2 lattice. Additional Raman peaks develop in nominally pure CaF2 with high etch pits density and U6+:CaF2 crystals. Part of additional Raman peaks in the experimental results, which are assumed due to vibration modes from F- interstitials and vacancies, are in well agreement with the theoretical predications by employing the Green-function formulation.
文摘Recently, ArF iininersion lithography has been considered as a promising method after ArF dry lithography by a factor of refractive index n of the liquid filled into the space between the bottom lens and wafer, in the case of 193-nm exposure tools, water （n - 1.44） has been found as the best liquid, We explore the NA/σ＇s dependence of depth of focus （DOF） under 3/4 annular and 3/4 quasar illumination by resist imaging simulation, Line/space pairs of line-to-space ratios 1：1, 1：2, 1：4 on binary mask are considered. Finally, we explored the high NA＇s dependency of DOF and gaw~ the explanation for the peak value of DOF through three-beam imaging process, MicroCruiser 2.0, Prolith version 8,0,2 and k2 factor based on the Rayleigh equation.
